Serial femtosecond (fs, 10−15 seconds) crystallography (SFX) using X-ray Free-Electron laser (XFEL) radiation is an emerging method for three dimensional (3D) structure determination that extracts structural information from nanometer (nm, 10−9 meters) to micron (micrometer, μm, 10−6 meters) sized crystals. This method relies upon intense X-ray pulses that are sufficiently short to pass through the sample before the onset of significant radiation damage (diffraction-before-destruction). SFX therefore promises to break the correlation between sample size, damage and resolution in structural biology. In this approach, a liquid microjet is used to introduce randomly oriented crystals into the XFEL beam. Structures with less than 2 Ángström (Å, 1 Å=10−10 meters) resolution have been solved using the method. SFX is unique from standard crystallography in that particle sizes on the order of microns dispersed in aqueous solutions are used instead of a single large crystal (that takes months of method development to grow) mounted on a loop or grid. One known method to deliver sample to the x-ray interaction region is the Gas Dynamic Virtual Nozzle (GDVN, e.g., see Shapiro, Chapman et al. 2008, DePonte et al., 2008, 2009, 2011, and Ganon-Calvo et al., 2010). A thin liquid jet is formed from a highly pressurized liquid reservoir and a high pressure sheath gas flow from concentric capillary tubes. The thin jet is subjected to femtosecond X-ray pulses (e.g., see Barty, Caleman et al. 2011; Chapman, Fromme et al. 2011; Hunter, DePonte et al. 2011; Lomb, Barends et al. 2011; Aquila, Hunter et al. 2012; Johansson, Arnlund et al. 2012; Koopmann, Cupelli et al. 2012).